EEG’s and Seizure Disorders Flashcards
what cell in the brain are responsible for the waves we see in the EEG?
The EEG is the leading test used to help diagnose which condition?
pyramidal cell postsynaptic potentials within the cortex.
seizures
The temporal resolution (ms) for which of these EEG is much greater: MRI, EEG, CT?
what is epilepsy?
EEG
recurrent seizures
Where do Epileptic Seizures start?
what should we remember about non-epileptic seizures?
Non-epileptic seizures can be divided into what?
the brain
they dont happen by changes in brain electrical activity
Can be divided into Organic NES, and Psychogenic NES.
what are these?
- Ictis (ictal)
- Postictis (ictal)
- Interictal
- Status epilepticus
- Ictis (ictal):
- Postictis (ictal): Period immediately following the seizure.
- Interictal: Period between seizures.
- Status epilepticus: Continuous seizures or clusters of seizures.
what are the types of epileptic seizures?
- Generalized seizures
- Generalized tonic clonic
- Myoclonic
- Absence
- Atonic
how do we define a generalized seizures?
Affect both hemispheres from the beginning of the seizure.
Loss of consciousness occurs for varying periods of time.
how do we define a Generalized tonic clonic?
‘Grand Mal’. Tonic phase includes stiffening of the limbs, clonic phase is jerking of the limbs and face.
identify the parts of this EEG during a tonic-clonic seizure
how do we define a myoclonic seizure?
hwo do we define an absence seizure?
Rapid, brief contraction of body muscles. Usually involves arms or feet/legs (both sides of body)
Periods of lack of awareness, usually lasting less than a minute.
what is another name for absence seizure?
how do we define atonic seizure?
‘Petit Mal
Abrupt loss of muscle tone.
what is Myoclonus?
is it normal or abnormal?
Brief, involuntary twitching of a muscle or a group of muscles.
normal
what are Types of Epileptic Seizures (Partial)?
how do we differenciate each?
what is a partial seizure?
Simple partial involves no loss of consciousness. Complex partial consciousness is lost or impaired.
partial seizure: area of seizure is limited to one region of the body.
what are the Types of Seizures Not Related to Epilepsy (NES)?
- First Seizures: One time only (induced by drugs, anesthetics, or unknown).
- Febrile Seizures: Seizures occurring during high fever in children.
- Dissociative Seizures: Looks like a seizure but no change in EEG. PTSD, panic disorder, are examples, as are factitious (Munchausen’s).
- Organic causes: Diabetes, syncope, migraine, stroke, tumor, etc.
what is Pre-eclampsia?
What is Eclampsia?
- High blood pressure and elevated levels of protein in urine in pregnant women.
- Tonic-clonic seizures (the eclamptic convulsion).
what is the Leading cause of maternal and peri-natal death?
Eclampsia
what causes seizures?
- Neurotransmitter imbalance: Low GABA levels in some patients. Some anti-seizures meds are GABAergic.
- Brain damage/trauma/disease: Irritative lesions can result in seizures.
- Environmental: Drug use or disuse, lack of sleep, stress, toxins.
What are the most frequent point of origin of seizures?
Temporal lobe seizures often preceded by what?
Motor cortex and temporal lobes
auras or hallucinations.
what is the Treatment of Seizures?
- Anticonvulsant meds: Dilantin (phenytoin), Tegretol (carbamazepine); many many more.
- Surgical removal of focal area (if a focal area can be identified).
- Diet restrictions (i.e. young children with phenylketonuria). ‘The Ketogenic Diet’
- Vagus nerve stimulation (VNS): Stimulating
electrode ‘wrapped’ around the left vagus
nerve (less cardiac effects than the right).
what is another name for Psychogenic non-epileptic seizures?
how do you treat this type?
dissociative seizures
do not originate from physical causes, thus are treated with therapy and often adjunct meds
what structures are involved in sleep?
- Reticular Formation
- Serotonin (5-HT)
- Adenosine
- Acetylcholine
- Hypothalamus
what does each do?
- ARAS: Ascending Reticular Activating System (the part of the RF involved in Sleep/Waking).
- Midbrain ARAS: ‘Drives’ cortex.
- Pontine ARAS: Turns off midbrain (for sleep).
which structure of the reticular formation generates REM sleep (and somaticmuscle inhibition). = Sleep is an active process.?
Pontine ARAS
how does the midbrain ARAS get turned off?
how will a Midbrain lesion affect your consciousness?
how will a Pons lesion affect your consciousness?
when 5-HT neurons in pontine RF project to midbrain and get activated
loss of consciousness (can’t ‘drive’ cortex).
constant wakefulness (can’t turn off the midbrain).
5-HT depletion will cause?
insomnia
when does Adenosine accumulate?
Adenosine A1 receptors are located where?
ACh neurons are involved in what?
Activation of A1 receptors results in what?
during period of high ATP use
in the ARAS.
arousal
inhibit ARAS, resulting in sedation/sleep
what part of the hypothalamus gets active during non-REM sleep?
A Bilateral lesion of the anterior nucleus will result in what?
Hypothalamus also involved in what ?
anterior and pre-optic nucleus
insomnia.
Circadian sleep cycle
how does the circadian rhythm get set?
Circadian rhythms relating to sleep peak at two time periods, what are these?
Light — Optic nerve — Hypothalamus —
Suprachiasmatic Nucleus — Brainstem.
3am-5am, and 3pm-5pm
